Technical Field
The present invention relates to a step up/down switching regulator, and more particular to a step up/down switching regulator which converts and outputs an input voltage into a predetermined output voltage.
Description of the Related Art
In recent years, electronic apparatuses mainly employ secondary batteries as rechargeable batteries. While power saving is always requested in the electronic apparatuses, a step up/down switching regulator which can supply power from the secondary batteries with high efficiency is widely used.
In the step up/down switching regulator consuming a relative large amount of current, a reduction in current consumption contributes to a reduction in current consumption of the electronic apparatuses in a standby mode. Thus, there has been employed a technology in which a short circuit is provided to short-circuit the input and the output of the step up/down switching regulator, and the input and the output of the step up/down switching regulator is short-circuited at the time of a light load to stop a switching operation so that the current consumption of the electronic apparatus itself is reduced.
However, the step up/down switching regulator has a large-sized output switch to regulate an input voltage compared to a step up type or a step down type, and the number of switches is also large. Therefore, when a short circuit is inserted in the step up/down switching regulator to make the input and the output thereof short-circuited, a chip occupies a large size depending on a magnitude of an impedance of the short circuit, so that the cost of the chip and a space for mounting the chip in the electronic apparatus are increased.